1. Field of the Invention
The present invention relates to resinoid bonded grinding wheels employing ultra-hard abrasives such as cubic boron nitride or diamond and more particularly to resinoid bonded grinding wheels with support members made of heat insulating materials.
2. Description of the Prior Art
A prior grinding wheel employing cubic boron nitride or diamond abrasives is generally formed with a metallic support member on which is affixed a grinding element consisting of cubic boron nitride or diamond abrasives bonded by a bonding matrix.
A grinding machine which is provided with such a grinding wheel is capable of a precision grinding operation even in a dead-stop grinding operation. However, since a support member is made of a metallic material, such as cast-iron or aluminum-base alloy, which has a relatively high thermal conductivity and a high rate of thermal expansion, the grinding wheel is caused to expand by heat transmitted from bearing members and the grinding area between the grinding wheel and a workpiece, thereby bringing inaccurate grinding results after grinding a certain number of workpieces.
It is, therefore, most advantageous to provide a grinding wheel wherein a support member is made of a heat insulating material which has a low thermal conductivity for preventing transfer of heat to the entire body of the support member and for preventing the thermal expansion of the grinding wheel.